They say 30,000 hours. As for the pq you see in our showrooms, the current BV4s & (within a month or so) BV9s ship with ACM systems that calibrate color over the life of the panel, so theoretically you'll get comparable pq over the full life of the panel. I have to say, though, we're currently selling off a 720p 50" with about 2 years of showroom wear on it and it looks better than any panel I've seen on display outside our store. I think it's a pretty good investment either way.
There is scarcely anything in this world that some man cannot make a little worse and sell a little more cheaply. The person who buys on price alone is this man's lawful prey. - John Ruskin